def adjust_gamma(image, gamma=1.0):
invGamma = 1.0 / gamma
table = np.array([((i / 255.0) ** invGamma) * 255
for i in np.arange(0, 256)]).astype("uint8")
return cv2.LUT(image, table)
elderly = cv2.imread("../../recursos/imagenes/Presentaciones/PSIM/elderly.jpg")
elderly_gray = cv2.cvtColor(elderly, cv2.COLOR_BGR2GRAY)
plt.imshow(elderly_gray, cmap="gray", vmin=0, vmax=255)
plt.show()
elderly_hist = cv2.calcHist(elderly_gray, [0], None, [256], [0,256])
plt.plot(elderly_hist, color="red")
plt.show()
elderly_gray_light = adjust_gamma(image=elderly_gray, gamma=2)
plt.imshow(elderly_gray_light, cmap="gray", vmin=0, vmax=255)
plt.show()
elderly_hist_light = cv2.calcHist(elderly_gray_light, [0], None, [256], [0,256])
plt.plot(elderly_hist_light, color="red")
plt.show()
elderly_gray_dark = adjust_gamma(image=elderly_gray, gamma=0.3)
plt.imshow(elderly_gray_dark, cmap="gray", vmin=0, vmax=255)
plt.show()
elderly_hist_dark = cv2.calcHist(elderly_gray_dark, [0], None, [256], [0,256])
plt.plot(elderly_hist_dark, color="red")
plt.show()
elderly_gray_lowcontrast=np.uint8(0.1*elderly_gray)+172
plt.imshow(elderly_gray_lowcontrast, cmap="gray", vmin=0, vmax=255)
plt.show()
elderly_hist_lowcontrast = cv2.calcHist(elderly_gray_lowcontrast, [0], None, [256], [0,256])
plt.plot(elderly_hist_lowcontrast, color="red")
plt.show()